<!doctype html>
<html lang="ko">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script src="../jquery-latest.js"></script>
    <style>
        div{}
    </style>
    <script>
        $(function(){
            $("input.required").prop("required", "true");
        });
    </script>
</head>
<body>

<form action="" method="post">
    <input type="text" name="first_name" maxlength="150" title="정보입력창1" class="required">
    <input type="text" name="first_name" maxlength="150" title="정보입력창2" class="required">
    <input type="text" name="first_name" maxlength="150" title="정보입력창3" class="required">
    <input type="submit">
</form>

<a href="http://stackoverflow.com/questions/19166685/jquery-add-required-to-input-fields">LINK</a>

</body>
</html>